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    1. Introduction to computers
      1. Why Computers?
      2. Different types of computers
        A. Microcomputers or personal computers
        1. Desktop computers
        2. Notebooks
        3. Network computers
        4. Handheld personal computers
        B. Workstations
        C. Minicomputers or midrange computers
        D. Mainframe
        E. Supercomputers
              CHAPTER 1.1: Introduction to Computers

              Chapter Objective: Introduce the learners to computers, the need to learn using them, and the various types of computers

              Computer is an electronic device used to store data, process it, and convert it into information that is useful to people. Computers perform this function by following specific programmed instructions. These programmes give a direction and purpose to the functioning of computers. In this course we will discuss why computers are necessary and the different types of computers.

              TOPIC 1.1.1:Why Computers?

              Topic Objective: Explain the need to learn computers

              In the past decade or so, we have witnessed a spectacular rise in use of computers, both in terms of new users as well as new ways of using them. So, we find that on the one hand, someone's grandparents are learning to use computers to communicate with their grandson residing in a different country; on the other hand, a computerized chip inside a heart patient's body is ensuring her a healthy life. Already, we are in a world where living without computers is difficult to imagine. The increasing presence of computers in our lives has made it essential for everyone to learn how to use them. Over the past decade, computers have been made more user-friendly and as a consequence increasingly more people are using computers. It also means that those who do not know how to use computers are at a disadvantage.

              As we will learn in the next topic, there are various types of computers but one of the most popular types of computer is a PC or personal computer, and our discussion in this chapter (as throughout this course) will focus on the PC. The many advantages of learning to use computers include:

              1. Employment options: As computers become commonplace in work environment, basic computer knowledge has become a pre-requisite for most jobs. This is especially true in the urban environment of the metros and other big (A class and B class) cities. Therefore, employers are more likely to hire a person who already knows how to use computers. Moreover, knowledge of computers also increases the options and opportunities for self-employed people (desktop publishing is one of the most common self-employment opportunities).
              2. Communications: With the advent of Internet, computers have proved to be an efficient and cheaper tool for communicating with colleagues, friends and family. As per your need, you may use tools like chat and Internet telephony that allow you to communicate simultaneously with a single user or a group of users; or tools like Email in which electronic messages are sent to or received from a single user or a group of users, with a lag of time. This is a faster and cheaper way of communicating, and also allows better collaboration by the users.
              3. Access to resources: Knowledge of using computers will allow you to access better resources for information and learning. CDROMs and Internet offer a wealth of information and knowledge on your desktop. Computers are a boon for students and researchers who can now access information sources around the world from their PCs.
              4. Better Information management: Computers and Internet are great tools to manage your personal information including schedules, finances, and documents. Computers are not only efficient tools for managing large amounts of information but they are also effective due to their reliability and speed.

              Instructor link: Classroom Activity on how to use computers

              Topic Exercises
              1. List four ways in which computers can be used.
              2. How do you intend to use computers after learning to use them?
              3. Mention three uses of computers that you knew before beginning this course.

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              TOPIC 1.1.2: Types of Computers

              Topic Objective: Provide an overview of the different types of computers including the variety of PCs

              Computers fall into five broad categories based on their size, range of power, and processing capabilities. These are Personal Computers, Workstations, Minicomputers, Mainframe Computers, and Supercomputers. We will briefly discuss each of these categories:

              A. Personal computers: Also referred to as microcomputers, Personal computers constitute the most popular category of computers. If you have encountered a computer, chances are that it was a personal computer. These are small systems intended for use by one person at a time. Based on their usage and the functions that they can perform, PCs are of the following types:
              1. Desktop computers: These are the most common type of personal computers in use today. They are small enough to fit on a desk but too big to carry around. Desktop computers have several components such as a display screen, a system unit, a keyboard, and a mouse. The system unit could be a horizontally oriented or vertically oriented (also called towers). There are several external components that can be attached to a desktop such as a printer, scanner, speakers or headphones. The configuration of a PC is usually flexible and can be modified according to the needs of usage. We will discuss desktop computers in detail in the next chapter. 

                Instructor link: Classroom activity on Desktop computers

              2. Notebook computers: Popularly known as laptop computers, they are small computers usually measuring 8 inch by 11 inch and weighing between 1.8 Kg to 3.6 Kg, and can be carried around in a briefcase or a separate case. These are fully-functional computers with a small display screen, keyboard, a touch-sensitive trackpad to work as mouse and a built-in CPU all in a single compact unit. Notebooks can work on special batteries or alternating current (plug-in) and tend to be more expensive than a comparable desktop PC. 
              3. Network computers : Network personal computer or net PC is a less powerful personal computer, with minimal processing power, memory and storage. A net PC is usually connected to a network server which provides it the necessary software and space for storage. These are usually used in situations where a user has to perform limited tasks that do not need all the power and features of a personal computer.
              4. Handheld personal computers: These are miniature computers that fit in a user's palms. These have a very small screen and keyboards and are without disk drives but memory could be added through PC cards or other means. Most of these devices are Internet capable and can be connected to a computer for exchanging data. Personal Digital Assistants (PDAs), Cellular phones with Internet, email and fax facilities are a few types of hand held computers. PDAs are most popular handheld computers and are usually used for special applications such as taking notes, storing contact information, and managing schedules. Most PDAs come with an electronic pen that is used to write on a touch sensitive screen.
              B. Workstations - These are specialized computers meant for single users, with most features of a PC but the processing power of a minicomputer. These machines are usually used by scientists, engineers, graphic designers, animators and senior programmers. These machines have advanced processors, more RAM, more storage capacity than personal computers, and come with large, high-resolution display screens. Workstations are also used as servers on personal computer networks and as web servers.

              C. Minicomputers - These are also referred to as mid-range computers because their capabilities lie between mainframeand personal computers. These can handle input and output needs of several terminals and are usually used as servers in computer networks with hundreds of computers.

              D. Mainframe computers - These are large-sized computers used in big organisations where many people access same data from huge databases. A mainframe computer is connected to several terminals that may or may not have their own processors. People work from these terminals and share the power and storage capacity of the mainframe to process and save huge amounts of data. Large mainframe systems can handle input and output needs of several thousand terminals. These are usually found in government departments, airlines reservation system or banks.

              E. Supercomputers- These are the most powerful, fastest and the largest computers. They process huge amounts of data and are used to handle large and highly complex problems that require extreme calculating power. Some of the areas where these computers are used are weather forecasting, nuclear technology and advanced scientific research

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              Topic Exercises

              1. Four different kinds of Personal computers are desktop computers, _____, Network computers, and _____.
              2. The computer that can be carried around in a briefcase is called _____.
              3. Mid-range computers are also known as _____.
              4. The computer smaller than a supercomputer but bigger than the mid-range computer is _____.
              5. The fastest and most powerful computers are called _____.
              6. List three components of a Desktop computer.
              7. In which computer is a trackpad usually found?
              8. Which computers are most likely to be found in a bank or a large airline reservation office?
              9. Which computer offers users mobility but much less processing power than a desktop?
              10. Describe the following:
              1. Pixel
              2. Database
              3. Terminal
              4. Workstation
              5. Server
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              Classroom Activities

              Need to learn computers

              Discuss with the students the different areas in which they have encountered use of computers. Also discuss the various uses of computers at home and in workplace.

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              Desktop Computers

              Describe the different components of a desktop to the students and ask the students to touch each component while the instructor explains the component and its function.

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              Term Explanation


              Raw facts, numbers, letters, or symbols that the computer processes into meaningful information.

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              When data is collected and organised into a specific structure so that it is easily usable, it is called a database.

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              Whenever data or instructions are transferred from a user or another hardware device in to the computer, it is called input.

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              Any data, information or instruction coming out of the computer is called its Output.

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              PC is the commonly used abbreviation for personal computer

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              It is a small piece of hardware in the computer that interprets and executes program instructions, and manages various functions of input, output and storage devices.

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              RAM refers to Random Access Memory. This is the read/write memory of the computer. Data is written to and read from this memory when you are using the computer. It is used to store data and application programs. However, RAM is volatile and requires constant supply of power and whenever the system is turned off, all contents of RAM disappear.

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              It is the degree of sharpness of an image, and is determined by the number of pixels on a screen.


              A dot on the screen that expresses a portion of an image on a computer screen

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              A terminal is a monitor, a keyboard and sometimes a pointing device connected to a computer network. Terminals may or may not have their own processing power.

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              It is a flat, small square surface on a laptop. Trackpad is touch sensitive and is used as a pointing device like a mouse is used for a desktop. The user controls the movement of the pointer on the screen by touching his finger on the surface of the trackpad and moving it across this surface. This is why it is also called touchpad.

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              It is the central computer of a network of computers, usually used for shared storage. It may store software applications, databases, and data files for the users of the computer network.

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